[leetcode] Climbing Stairs

最新推荐文章于 2019-02-15 20:44:04 发布

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本文介绍了一个经典的动态规划问题——爬楼梯问题。该问题要求计算出到达楼梯顶部的不同方式的数量，允许每次上1阶或2阶。通过一个简洁的C++代码示例，展示了如何使用迭代的方法高效解决这一问题。

From : https://leetcode.com/problems/climbing-stairs/

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

class Solution {
public:
    int climbStairs(int n) {
        if(n <= 0) return 0;
        if(n <= 2) return n;
        int pre = 1, post = 2, t;
        for(int i=3; i<=n; i++) {
            t = pre;
            pre = post;
            post = t + post;
        }
        return post;
    }
};